Adjustable cams



F. C. HOLMES Aug. 5, 1969 ADJUSTABLE CAMS Filed Sept. 7, 19s? hml i 1., mm W Z i. w .W, i

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United States Patent ce 3,459,066 ADJUSTABLE CAMS Frank C. Holmes, Trumbull, 'Conn., assignor to The US. Baird Corporation, Stratford, Conu., a corporation of Connecticut Filed Sept. 7, 1967, Ser. No. 666,062

Int. 'Cl. F16h 53/00 US. Cl. 74-568 8 Claims ABSTRACT OF THE DISCLOSURE An adjustable cam for use in spring making machinery producing coil springs having non-circular body sections. The cam includes a plurality of segmented camming members positioned in pairs about the periphery of the cam, the two members of each pair being adjustable relative to each other and to other pairs.

Background of the invention One of the most efficient methods for producing coil springs utilizes a machine wherein wire is fed through an elongated quill. As the wire leaves the quill, it impinges against forming tools which, depending upon their position, cause the wire to assume various configurations and form, for example, end loops and body loops of the coil spring. When the spring is fully formed, it is cut from the wire stock by means of a cutter tool. The various tools are properly positioned relative to the advancing wire and the quill end by means of a cam. One such cam, for example, is described in my United States Patent 3,338,112 of Aug. 29, 1967.

In producing coil springs having round bodies, the forming tool remains positioned in substantially the same location throughout the interval during which the body coil is being formed. However, there are certain applications which require non-circular coil springs. Such coils may have, for example, two straight opposed sides and either curved or relatively straight short edge sections. In forming springs of this type, it is necessary for the forming tool to periodically move in and out relative to the quill between two fixed positions. In the past, the cams for controlling this movement have been of solid construction. This construction was undesirable for several reasons. First, a considerable amount of trial and error was required before achieving the proper shape. Second, the cam could be used for only one type of spring. Third, the cost was high both in terms of producing the cam initially and because a different cam was required for each type of spring.

Accordingly, it is a primary object of the present mvention to provide an adjustable cam having a substantial degree of flexibility.

Summary of the invention The object of this invention is achieved by means of a cam including a plurality of camming segments having high lobes. These camming segments are individually adjustable and are arranged in pairs, the members of each pair being positioned back to back so that the high lobe portions are adjacent and cooperate to form a high dwell portion. As the cam segments are fully adjustable relative to one another, the lengths and spacing of the dwell portions may be varied and, as the segments are removable, the number of dwell portions may be varied.

Brief description of the drawing The various features of one embodiment of a cam constructed in accordance with this invention are illustrated in the drawing wherein:

3,459,066 Patented Aug. 5, 1969 FIG. 5 is a perspective view of a cam segment as seen from its inner side.

Description of the preferred embodiment The cam of the invention is illustrated as mounted on a shaft S and in contact with the rider R of a tool control arm A. Portions of this cam are quite similar to that illustrated in my above-mentioned US. Patent 3,338,112. Thus, there is provided a substantially cylindrical hub 10 defining a central opening 12 for engaging the shaft S. The hub is provided with a radially extending flange 14 which encircles the hub centrally of its two ends. The flange 14 includes a pair of circular raised tracks 16, 1-8 on its two opposite surfaces. These tracks are of square cross-section and are concentric with the hub 10. On the left side of the cam, as viewed in FIGS. 1 and 2, are mounted camming members 20, 22, 24 and 26. These camming members are similar to those described in the aforementioned patent and include a curved edge shaped to conform to hub 10 and an arcuate groove for receiving the tracks 16 or 18. Adjusting holes 28 permit the cams to be adjusted relative to the hub by means of a separate pinion rotatable in the adjusting hole 28 and against the teeth of the cup shaped gear 30. This gear is retained on the hub by means of clamping screws 32 which serve to tighten the gear 30 against the camming members 20, 26 to clamp them against flange 14. A corresponding gear 34 on the opposite end of the hub is secured by clamping screws 36 which serve to clamp camming members 22, 24 against flange '14. It will be noted that all of screws 32, 36 are adjustable from one side of the cam, the heads of the clamping screws 36 being recessed within suitable openings in gear 30.

The spring body-forming portion of the cam comprises a plurality of cam segments 38a-38k positioned against one side of the flange 14 and a plurality of matching cam segments 38a to 38k positioned against the opposite side of flange 14 and in paired relationship with the cam segments 38a-38k.

A representative cam segment 38 is illustrated in detail in FIGS. 4 and 5. From these illustrations it will be seen that the body portion 40 is in the form of a segment of a disc and that the narrow end 42 is curved to mate with the circular hub 10. Extending from the wide end is a high lobe 44. The end of lobe 44 includes a dwell portion 46 which is concentric with the cam hub. The outer corners of lobe 44 are rounded to form a relative gradual drop off 48 and a relative steep drop off 50 at either end of the dwell portion 46. The dimensions of the individual segments may be varied to suit the application. However, in one embodiment the dwell portion 46 was A inch. The radius of the drop off 50 was inch, and the radius of drop off 48 was ,4, inch.

The outer surface 52 of cam segment 38 is substantially planar, as is illustrated in FIG. 4. The inner surface, however, is cut away to form a recess 54 at the narrow end separated by a thickened central portion 56 from the thinner lobe 44, thus forming an inner arcuate shoulder 58 and an outer arcuate shoulder 60. Machined into the recess 54 is an arcuate groove 62 of square cross section and dimensioned to mate with track 16 or 18. All of outer shoulder 60, inner shoulder 58, groove 62 and end 42 are concentric with one another and with the center of the cam hub. Passing through the central portion 56 of the cam segment is a tapped clamping hole 64.

The manner in which the cam segments are mounted in the cam of this invention is illustrated in FIGS. l-3. It will be noted that the segments are mounted in paired back to back relationship. Recesses 54 receive flange 14 and grooves 62 are slidably positioned on the respective tracks, 16 or 18. In the illustrated embodiment there are eleven such pairs of cam segments. It will also be noted that, although the lobes of each pair are not aligned, they do overlap sufiiciently to form a high dwell surface for contacting rider R. The length of this high dwell surface may, of course, be varied by adjusting the degree of overlap between the segments of each pair. The positional relationship of the segments on either side of the flange is established by means of arcuate clamping members 66, 66'. These clamping members are curved bars defining arcuate slots 68, '68 aligned with the respective clamping holes 64. A screw 70, and washer 72 secures each of the segments to its corresponding clamping member.

It will now be noted that the segments 38a38k, together with their corresponding clamping member 66 and screws 70, form a unitary assembly mounted against the flange 14. Similarly, segments 38a38k', together with clamping member 66' and screws 70, form another assembly mounted on the opposite side of the flange 14. These two subassemblies may be clamped in position in the same manner as camming members 20, 22, 24, and 26 by means of the action of clamping screws 32, 36, and cup-shaped gears 30, 34.

The position of rider R, intermediate the high dwell positions established by lobes 44 of segments 38, is established by a plate-like camming are 74. As will be obvious from FIG. 3, the lobe portions of segments 38 are separated sufficiently to receive and support the camming arc thercbetween against the respective shoulders 60. The are is held in position by means of screws 76 extending through segments 38b and 381', respectively, which are drilled for this purpose.

It is believed that the flexibility of the cam of this invention will now be apparent to those skilled in the art. In order to adjust the position of the respective cam lobes, the clamping action of the gears 30, 34 may be released by loosening screws 32 or 36. Thereafter, the individual segments may be adjusted by loosening screws 70 sufficiently to permit the segments to be slid along track 16 or 18 to the desired position. It will also be apparent that, by means of the present invention, all of the objectives hereinbefore set forth have been achieved.

It will be understood by those skilled in the art that a number of modifications and variations may be made in this invention without departing from its spirit and scope. Accordingly, the foregoing description is to be construed as illustratitve only, rather than limiting. This invention is limited only by the scope of the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An adjustable cam which comprises: hub means having a first and a second end; flange means extending radially outward from said hub means around its periphery; first and second tracks formed on and on opposite sides of said flange means, each encircling said hub means; a plurality of pairs of substantially similar camming members, the members of each pair being slidably disposed on said tracks on opposite sides of said flange means and including respective lobe portions cooperatively forming a high dwell portion, said pairs being disposed to define low portions intermediate said high dwell portions; means for securing said camming members in preselected positions relative to one another; and means for clamping said camming members in preselected positions relative to said hub means.

2. The cam of claim 1 wherein said means for securing comprises an arcuate clamping member and means for detachably securing thereto a plurality of those camming members on one side of said flange means.

3. An adjustable cam which comprises: hub means having a first and a second end; flange means extending radially outward from said hub means around its periphery; first and second track means on opposite sides of said flange means and encircling said hub means; a plurality of pairs of substantially similar camming members, the members of each pair being slidably disposed on said track means on opposite sides of said flange means and including respective lobe portions cooperatively forming a high dwell portion, said pairs being disposed to define low portions intermediate said high dwell portions; an arcuate member mounted to extend between said high dwell portions to define intermediate low dwell portions; means for securing said camming members in preselected positions relative to one another; and means for clamping said camming members in preselected positions relative to said hub means.

4. An adjustable cam which comprises: hub means having a first and a second end; flange means extending radially outward from said hub means around its periphery; first and second track means on opposite sides of said flange means and encircling said hub means; a plurality of pairs of substantially similar camming members, each in the form of a substantially planar disc segment, the members of each pair being slidably disposed on said track means on opposite sides of said flange means and including respective lobe portions cooperatively forming a high dwell portion, said pairs being disposed to define low portions intermediate said high dwell portions; means for securing said camming members in preselected positions relative to one another; and means for clamping said camming members in preselected positions relative to said hub means.

5. The cam of claim 4 wherein said lobe portions extend outwardly from, and are narrower than, the wide end of said segment.

6. The cam of claim 4 wherein one side of each of said camming members defines a recess engageable with said flange means.

7. The cam of claim 5 wherein said lobe portions define recesses on the facing sides of said camming members, said recesses terminating in circumferential shoulders spaced radially inward from said high dwell position.

8. The cam of claim 7 wherein an arcuate member is mounted against said shoulders intermediate the lobe portions of said camming members and extending between said high dwell portions to define intermediate low dwell portions.

References Cited UNITED STATES PATENTS 1,940,598 12/1933 Larkin 66-156 2,800,808 7/1957 Capelle et a1 74-568 XR 3,069,936 12/1962 Gideon 74--568 XR 3,151,500 10/1964 Kurz 74568 3,264,897 8/1966 Berger 74-568 FOREIGN PATENTS 555,648 9/1943 Great Britain.

FRED C. MATTERN, 111., Primary Examiner F. D. SHOEMAKER, Assistant Examiner 

